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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An assessment of the effect of grading of perlite on ultimate strength in lightweight concrete.

Winter, Adrian Jeremy January 1998 (has links)
A RESEARCH REPORT SUBMITIED TO THE FACULTY OF ARCHITECTURE. UNIVERSITY OF THE WITWATERSRAND, JOHANNESBURG, FOR THE DEGREE OF MASTER OF SCIENCE IN BUILDING / This research project is an investigation into the effect of the grading of perlite lightweight aggregates on the resultant concrete strengths. Lightweight concretes are reviewed. Perlite, as a lightweight aggregate, is assessed. Grading theory for aggregates and in particular lightweight aggregate is analysed. A series of mix designs are proposed with manipulation of the grading of the perlite as the only variable. This is so that variations in compressive strength and density may be assessed in terms of the grading of the perlite. Those mixes are undertaken and tested for compressive strength and dry density. In this research project compressive strength is considered a benefit, while mass is considered a disadvantage. The performance of a lightweight concrete is assessed firstly in terms of the Power Factor. The Power Factor is the compressive strength divided by the dry density of a concrete. The performance of lightweight concretes produced with Perlite aggregate is assessed secondly in terms of the Cement Content factor. The Cement Content Factor is the Power Factor divided by the Cement Content. This factor has the effect of creating a common denominator of the cement content. An evaluation of the results yields the conclusions detailed in chapter Eight, the principal two being: • The optimal perlite grading tested was a monodisperse, single size fraction, of between 600 and 1180 microns. • The most practical measure for manufacturers to improve the performance of lightweight / Andrew Chakane 2019
2

Feasibility study on polyolefin reinforced natural fibre foam composites for structural applications.

Adediran, Kehinde Mojisola January 2014 (has links)
M. Tech. Civil Engineering / Composites of synthetic polymers and natural organic materials, used as fillers, find a wide application due to biodegradability, renewability, low-cost recyclability, low specific gravity, low weight, and non-abrasiveness to processing equipment. These composites find application in various areas such as automotive interior, households, ornaments, building, and packaging. In spite of these advantages, use of these materials as reinforcement or filler in thermoplastics in general and in polyolefin in particular, is not as extensive as expected. This is due to their limited thermal stability during processing, poor dispersion in the thermoplastic melt and limited compatibility with the matrix as well as poor toughness and stress transfer efficiency. The main objective of this research was to determine the suitability and performance of natural fibre reinforced polyolefin foam composite material as a possible construction material.
3

Recycled building materials : the likely impact on affordable housing in the Western Cape

Traut, Michelle January 2001 (has links)
Thesis (MTech (Built Environment))--Peninsula Technikon, 2001 / The construction industry globally, contributes between 18% and 24% of the GDP, and because of its labour intensive characteristics, contributes handsomely to total employment, forming important backward and forward linkages with the rest of the economy. Nevertheless, the extent and sophistication of these linkages crucially depend on the relative development of the construction industry relative to the overall economy. In the developing countries, these linkages are not very strong because of the use of informal materials, which is not commercialised and whose opportunity costs are often zero, and the huge imports of construction materials used in the modem sector of the economy. However, whether in the developed or developing economies, the construction industry is a major contributor to economic growth and development by providing the necessary infrastructure that facilitates production, consumption and recreational activities. In fulfilling these activities, the construction industry generates huge wastes of which only a tiny proportion are recycled and reused. However, in economies and countries where adequate and functional housing is a problem mainly due to lack of affordability, recycling and reuse of construction waste is a necessary prerequisite to enhancing housing affordability in these countries. This is the current situation that South Africa finds itself "''here because of its past history of 'apartheid', economic opportunities and amenities were denied to the blacks. There is nowhere that this deprivation is more pronounced than in the built environment sector where housing shortages and general disamenities prevail. High levels of unemployment further exacerbate the situation, - - which is a consequence of low skills and high illiteracy-rates. Thus, housing demand and supply by this group of the population are most likely, on the evidence available, to fall predominantly within the low-income housing category. Presently, all households falling into this category rely on financial assistance from the government to facilitate low-cost housing consumption because of pervasive poverty, which itself is due to the very high unemployment rate, illiteracy, lack of skills and general deprivation: a legacy of 'apartheid' policies enforced by previous government. The dilemma however is how to meet the huge housing demand within the limited resources available to the government on the one hand, and on the other, to satisfy such demand without compromising the environmental sustainability of the physical environment. Thus, the thesis aims to determine ways in which the construction industry could contribute to the sustainability of the carrying capacity of the biophysical environment and enhance social sustainability by facilitating affordability through the possible reductions to construction costs through recycling and reuse. By means of questionnaires and detailed interviews, underscored by a qualitative research approach, the potential of construction recycling and the possible contributions to environmental sustainability and housing affordability are determined. At completion, it is expected that this work will not only contribute to existing knowledge but would be of significance in terms of policy formulation to construction industry practitioners, central and local government policy makers, and other governmental and non-governmental organisations operating in the area of housing.
4

Partnering with suppliers for quality improvement

Baliso, Unathi January 2010 (has links)
A dissertation submitted in fulfillment of the requirements for the degree Master Technology: Quality in the Faculty of Engineering at the Cape Penisula University of Technology / Uneven surfaces on national roads that often lead to difficulty and even danger can be extremely hazardous when wet, due to mud and cracks, and also create dust pollution for motorists, pedestrians, residents and business. The continuing use of low quality raw materials in producing hot mix asphalt for national roads, leads to regular maintenance at a very high cost. The quality aggregates (stone that is used to produce asphalt), and the quality of bitumen are often inadequate for the correct composition of hot mix asphalt. The mst important factors affecting initial and long term performance of the highways is the inferior pavement structure and condition, due to poor aggregates (raw material)from suppliers. The performance of asphalt i s largely determined by the characteristics of its constituents, the asphalt binder and aggregates.
5

Design, fabrication, production and erection of elements for a low cost housing unit

Nxumalo, Mutshutshu January 1999 (has links)
Thesis submitted in partial compliance with the requirements for the Masters Degree in Technology: Mechanical Engeering at Technikon Natal, 1999. / Housing is currently one of the most critical development areas in the Republic of South Africa (RSA). This developmental project forms part of a possible solution in the delivery of housing through mass production. The objective of this study is to establish a empathetic connection between modem geodesic construction and the traditional dome and to design an effective and efficient prefabricated dwelling unit suited to be easily built by semi-skilled persons. The success of this project will fulfill one of the major objectives of the RSA's Reconstruction and Development Programmes (RDP) - 'A better lifefor all'. / M
6

An evaluation of the Phragmites australis reed use by communities neighbouring the Tembe Elephant Park, Maputaland, KwaZulu-Natal, South Africa

Tarr, Jason Alec 30 March 2007 (has links)
The commercial harvesting of Phragmites australis reeds in the Tembe Elephant Park, Maputaland, KwaZulu-Natal was investigated to determine the impact of reed use on the Muzi Swamp. The reed quality in the harvesting areas within the Tembe Elephant Park has deteriorated over time, with the reeds in the harvested areas being by and large shorter and thinner than the reeds in the other areas of the reserve where harvesting is not allowed. The impact of continuous harvesting in combination with the accidental burning of certain areas in the Muzi Swamp was also found to be detrimental to reed production when compared to other treatments. Poor rural communities neighbouring the Tembe Elephant Park are dependant on the reed resource for both income supplementation and for use in the construction of dwellings. Reeds offer a cheaper alternative to the more western building materials, which is of utmost importance in an area where the mean yearly income is around ZAR 6000 per annum. The manufacture of prefabricated reed and forest timber huts by the local reed harvesters in the summer months would facilitate a winter only harvest, which is more beneficial and is integral to the improvement of the long-term reed quality in the Muzi Swamp. In addition, the cost of these proposed prefabricated reed and forest timber huts is approximately one third of the cost of a similar sized hut that is constructed from bricks and cement. Management recommendations for the controlled harvesting area in Muzi Swamp of the Tembe Elephant Park, as well as the section of the Muzi Swamp that is not afforded protection by Ezemvelo KwaZulu-Natal Wildlife, are also presented. / Dissertation (MSc (Wildlife Management))--University of Pretoria, 2007. / Centre for Wildlife Management / unrestricted
7

Waste management strategies employed on construction sites in Gauteng

Sibanda, Desire January 2017 (has links)
Thesis is submitted in partial fulfilment for the degree of Master of Science (Building) in Construction Project Management to the Faculty of Engineering and the Built Environment, School of Construction Economics and Management at the University of the Witwatersrand, Johannesburg, 2017 / There is a problem of construction waste on construction sites. However, there are various strategies that can be employed; not only on construction sites, but generally on construction projects from the inception of the project to manage construction waste more effectively. Construction waste management can loosely be defined as a function of controlling waste on construction projects to limit its generation and disposal but enhance reduce and recycling. Construction waste mainly arises from design changes, poor choice of construction materials, improper material specifications, inappropriate strategies employed or wrong strategies implemented; leading to poor management of waste on construction projects. Construction waste can be ‘physical’ or ‘non-physical’. Physical construction waste refers to tangible solid waste of materials emanating from construction activities. Non-physical waste pertains to waste of time and project funds in the form of unnecessary expenditure. The aim of this study is to identify waste management strategies utilized on construction sites in Gauteng. Pertinent literature provided a basis of the study. A cross-sectional survey using three construction sites in Gauteng: an office building project, a road project and a civil works project was adopted. The most common strategies were found to be –proper selection of construction materials, proper planning and logical sequencing of construction work activities on a project. There is a variety of branded materials hence the need for proper selection of materials. Further, there are a lot of factors that influence the flow of work activities hence the requirement to keep track and plan activities accordingly to counter distortions. It is acknowledged that strategies found to be common in Gauteng are basic techniques in controlling construction waste generation and the results tied back to the literature. It was established that technological tools like Building Information Modeling are not yet common in Gauteng. Improvements on usage of prefabricated components and offsite manufacturing of components is recommended to stakeholders of the construction industry. It is also logical to conclude that waste management strategies employed on construction sites in Gauteng are anchored on factors of economic viability and government policies. In their quest to make projects profitable and in their efforts to make construction projects compliant to regulations, as a result, construction contractors achieve reductions in waste generation on construction projects. Therefore what the study found out are mainly practices that could, in addition to achieving primary aim, contribute to waste reduction. These strategies identified are implemented primarily to achieve time, cost and quality objectives and thus indirectly waste reduction. / MT2018
8

Development of product quality management guidelines for informal small-scale brick manufacturing enterprises in Dididi, Limpopo Province, South Africa

Matsiketa, Khensani Eullen 18 May 2018 (has links)
MESMEG / Department of Mining and Environmental Geology / Although clay brick manufacturing has been going on for many years in South Africa, informal small-scale clay brick manufacturing enterprises are not officially regulated. Consequently, informal brick makers in the study area do not adhere to the demanding requirements of the South African National Standards for burnt clay masonry. Therefore, their clay bricks lack uniformity in terms of quality. Preliminary work revealed that over time, buildings constructed with these bricks develop cracks, thereby compromising safety. The importance of product quality management is not well understood in the informal brick manufacturing enterprises. As a result, they do not have any product quality management guidelines. The main purpose of this research was to develop the product quality management guidelines for ensuring quality in small-scale brick making enterprises in Dididi area. The specific objectives were to characterize the raw materials for clay brick manufacturing, identify and assess the technical problems of clay brick production, analyse the process of clay brick production and determine areas where product quality improvement is warranted. The research involved fieldwork which included soil sampling, analysis of clay brick production through the use of questionnaires and onsite observation of the production process, collection of samples of burnt bricks which were examined for compressive strength, water absorption as well as dimension measurements. These were then compared with the prescribed quality standards. Laboratory analyses of samples of raw materials were conducted and these included sieve analysis which was conducted in order to establish the particle size distribution of the raw materials; Atterberg limit tests were conducted in order to establish the physical characteristics of the soil. Chemical and mineralogical analyses were carried out to determine the chemical and mineralogical composition of the soil using XRF and XRD respectively. The textural characterisation of the material revealed abundance of sand sized particles and significantly low amounts of clay and silt. The plasticity of the soil used for bricks manufacturing in the study area was found to be ranging from slight to medium plasticity. Chemical analysis showed elevated silica contents with minor amounts of alumina and iron oxide. XRD analysis revealed the dominance of non-clay minerals with the highest concentration of quartz. The average compressive strengths of the tested brick samples for site A was 3.8, and 2.9 and 3.8 MPa for sites B and C respectively. The water absorption of the bricks was 13.5, 15.0 and 16.1% for samples from Site A, B and C respectively. The bricks dimensions met the recommended standards although their sizes were not uniform. v The survey conducted on brick manufacturing process revealed that the technical inefficiencies were mostly influenced by human and mechanical factors as well as the material inappropriateness. The production process was found to be too manual and labour intensive. Selection of the raw materials for brick manufacturing was based on indigenous knowledge and experience and most of the brick manufacturers lacked the prerequisite experience for making quality bricks. On the basis of the results of this research, it can be concluded that the materials used for manufacturing of clay bricks in Dididi are not well suited for making good quality bricks due to the reduced plasticity of the soil and the high concentration of quartz. These render the bricks brittle. It was also concluded that the production process also contributes to the poor quality of the bricks as the nature of the process was too manual. Selection of materials based merely on knowledge and experience and no scientific tests resulted in selection of inadequate materials which in turn affect the quality of the final bricks. It is therefore recommended that plastic clays be added to the raw clay materials to enhance its moulding property. In addition, materials such as internal fuels and anti-shrinkage materials should be incorporated into the process cycle to prevent cracking during drying and firing. Based on the findings of the analysis of the production process, it is recommended that mechanized techniques be employed in the operation and awareness training conducted to improve the understanding and skills of the brick manufacturers and to ensure production of good quality bricks. / NRF

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